The present invention relates to an oxygen concentration sensor for sensing the concentration of oxygen in an exhaust gas of an internal combustion engine, for example, and more particularly a sealing structure and a structure for leading out an electrode in the oxygen concentration sensor using a solid reference material as a reference oxygen partial pressure sensor.
In a prior oxygen concentration sensor with the solid reference material of this kind, the solid reference material has been used, as just mentioned. In the sensor, how to stably seal the solid reference material over a long period of time is an important problem. How to lead out an electrode located on the solid reference material side simply is another important problem.
Actually, however, there has never been any proposal to solve the above problems.